Add failing tests for dart2js' range-analysis.

tests/language/value_range2_test.dart

Index: tests/language/value_range2_test.dart
diff --git a/tests/compiler/dart2js_extra/constant_javascript_semantics2_test.dart b/tests/language/value_range2_test.dart
similarity index 52%
copy from tests/compiler/dart2js_extra/constant_javascript_semantics2_test.dart
copy to tests/language/value_range2_test.dart
index af4872fd2b066b46cfd00062dfb04b78f0bc6771..49a9b713a42ff05285540f8071a94661c3cf7d20 100644
--- a/tests/compiler/dart2js_extra/constant_javascript_semantics2_test.dart
+++ b/tests/language/value_range2_test.dart
@@ -2,20 +2,16 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// Make sure we use JavaScript semantics when compiling compile-time constants.
-// In this case we test that the value-range analysis uses JavaScript semantics
-// too.
-
 int inscrutable(int x) => x == 0 ? 0 : x | inscrutable(x & (x - 1));
 
 foo() {
-  var a = const [1, 2];
-  var i = 0x100000000;
-  if (inscrutable(i) == 0) {
-    i = 0x100000001;
-  }
-  i = 0xFFFFFFFFF & i;  // In JS semantics [:i:] will be truncated to 32 bits.
-  i = 0x100000001 - i;
+  int x = 0;
+  if (inscrutable(0) == 0) x = -2;  // x is now in range [-2 .. 0].
+  int y = 2;
+  if (inscrutable(0) == 0) y = 4;  // y is now in range [2 .. 4].
+  int i = y - x;  // i should be in range [2 .. 6].
+  i -= 4;  // i should be in range [-2 .. 2]. Actual value: 2.
+  var a = const [1];
   return a[i];
 }
 
@@ -23,3 +19,4 @@ main() {
   Expect.throws(() => foo(),
                 (e) => e is IndexOutOfRangeException);
 }
+